The given graph represents the variation of Z (compressibility factor =(PV)/(nRT)) versus P, for three real gases A,B and C. Identify the only incorrect statement.

The given graph represents the variation of Z (compressibility factor

1.	The given graph represents the variation of Z (compressibility factor =(PV)/(nRT)) versus P, for three real gases A,B and C. Identify the only incorrect statement.
Answer» For the gas A,a=0 and its dependence on P is linear at all pressures For the gas B, b=0 and its dependence on P is linear at all pressures. For the gas C, which is typical real gas for which neither a=0 nor b=0. By knowing the minima and the point of INTERSECTION, with Z=1, a and b can be calculated. At high pressure, the slope is positive for all real gases. Solution :Vander Waals. EQUATION is `(P+a/(V^(2)))(V-b)=RT` When `a=0,P(V-b)=RT` or `PV=RT+Pb` i.e. `Z=1+(Pb)/(RT)`. Thus `Zgt1` and INCREASES with INCREASE of pressure. Hence a is correct. When `b=0(P+a/(V^(2)))V=RT` or `PV+a/V=RT` i.e. `Z=1-a/(RTV)`. Thus `Zlt1` and decreases with increase of pressure.Hence b is correct. Statement d is also correct.